System and apparatus for dental prophylaxis

ABSTRACT

A dental prophylaxis handpiece is provided with a supply conduit through which the prophylaxis material is supplied directly to the center of the rotatable flexible cup or applicator. The configuration and mounting of the cup prevent admission of abrasive material to the bearings. A high pressure fluid actuated control system makes possible a quick-shot or small slug supply of the prophylaxis material by operation of a remote foot operated control. All of the functions of motor control, material supply, water flushing and air drying may be performed by the dentist by actuation of a foot control unit or other suitable actuating device.

This is a Continuaation-in-Part of application Ser. No. 254,330 filedMay 17, 1972 and now abandoned, which is a Continuation of applicationSer. No. 106,648 and now abandoned Jan. 15, 1971.

This invention relates to dental prophylaxis apparatus and particularlyto an improved dental handpiece and control system for supplyingprophylaxis materiaal or paste to the applicator cup on the handpiece.

In the practice of dental prophylaxis involving the cleaning andpolishing of the teeth it has been proposed, heretofore, that theprophylaxis material be supplied from a pressure source directly to theflexible applicator cup. Apparatus for such application of the fluidmaterial has been devised with a view to reducing the time consuming andinconvenient practice of picking up the material from a supplyreceptacle; this requires back and forth movement of the handpiecebetween the patient's mouth and the paste receptacle and interrupts thedentist's work. Furthermore, the quantity of paste required at the cupvaries during the prophylaxis treatment and it is desirable that thequantity of paste be easily controlled and also that the supply andcontrol of the paste be effected without requiring the dentist tointerrupt his work. Accordingly, it is an object of the presentinvention to provide a dental prophylaxis system including an improvedarrangement for minimizing the interruption of the dentist's work duringthe treatment.

It is another object of this invention to provide an improved apparatusfor controlling the supply of prophylaxis material to the applicator cupon a dental handpiece during the use of the handpiece.

It is another object of this invention to provide an improved dentalprophylaxis system of the type including a pressurized supply ofprophylaxis material for selectively controlling the amount of thematerial delivered to the applicator cup during the use of the cup in apatient's mouth.

It is a further object of this invention to provide a dental handpiecefor prophylaxis treatment utilizing a flexible applicator cup andincluding an improved arrangement for preventing the admission of theprophylaxis material to the bearing surfaces of the handpiece.

It is a further object of this invention to provide a dental prophylaxissystem including an improved control enabling the dentist to perform alltreatment functions without changing his hand position or removing thehandpiece from the patient's mouth.

Briefly, in carrying out the objects of this invention in one embodimentthereof, a dental prophylaxis system is provided which includes a dentalhandpiece having a passage for delivering through the head thereof asupply of dental prophylaxis material which flows from the passage intothe interior of a flexible applicator cup mounted on the handpiece to bedriven thereby. The configuration of the flexible cup and of itsmounting on the handpiece are such that the admission of the treatmentmaterial to the bearing surfaces of the handpiece is effectivelyprevented at all times and particularly during the use and distortion ofthe cup in the course of the treatment. The control system includes air,water and prophylaxis material supplies and selective controls fordelivering water, air or material to the patient's mouth during thetreatment. The controls are effected by operation of a foot controllerand allow the dentist to work without interruption and without shiftingthe position of his hand on the handpiece. A precise control of thesupply of prophylaxis material is efffected by a high pressure hydraulicdrive system which enables the dentist to use a tappping or jogging ofthe foot control to select a range of quantities of material from a verysmall quantity to a sufficient quantity to fill or overflow theapplicator cup. The control also may be actuated to provide a continuoussupply of material if desired.

The features of novelty which characterize this invention are pointedout with particularity in the claims annexed to and forming a part ofthis specification. The invention itself, however, both as to itsorganization and method of operation, together with further objects andadvantages thereof, may be best understood by reference to the followingdescription taken in connection with the accompanying drawings, inwhich:

FIG. 1 is a side elevation view of a dental handpiece embodying featuresof the invention;

FIG. 2 is a top plan view of the handpiece of FIG. 1;

FIG. 3 is an end elevation view partly in section of the handpiece ofFIG. 1;

FIG. 4 is an enlarged sectional elevational view of the head assembly ofthe handpiece of FIG. 1;

FIG. 4a is an enlarged view of a portion of the assembly of FIG. 4;

FIG. 5 is an enlarged elevation view of the forward end of the handpieceof FIG. 1;

FIG. 6 is a view similar to FIG. 5 with the front end of the handpieceturned to its flushing position;

FIG. 7 is a sectiional view taken along the line 7--7 of FIG. 5;

FIG. 8 is an enlarged view taken along the line 8--8 of FIG. 1;

FIG. 9 is an enlarged sectional view of aa portion of the handpiecetaken along the line 9--9 of FIG. 1;

FIG. 10 is a sectional elevation view of a water pressure amplifieremployed with the system of the invention;

FIG. 11 is a schematic diagram of the fluid and electrical ciricuits ofthe system of the invention; and

FIG. 12 is a face view of a flow control dial for the system of FIG. 11.

Referring now to the drawings, the handpiece illustrated in FIGS. 1, 2and 3 comprises an elongated cylindrical main body portion 10 and aportion 11 of reduced cross section to which is secured a detachable tip12 having a head 13. A motor (not shown) is arranged within the mainbody portion 10 and through a drive connection arranged in the portion11 and the tip 12 rotates a detachable flexible applicator cup 14. Inthis embodiment, the motor within the main body portion 10 is an airmotor or turbine driven by air supplied through a flexible conduit 15arranged in a main tubing or enclosure 16. An electric motor may also beused in which case the power leads would extend through the tube 16instead of the motor air supply tube 15. The tubing 16 is secured to thehandpiece by a clamping member 17 which fastens the tubing 16 securelyto a tubular or channel-like extension 18 extending rearwardly from thebody portion 10. In addition to the tubing 15, the tube 16 carries fouradditional fluid supply tubes 19, 20, 22 and 23 which are fluiid controlsupplies and drying air and flushing water supplies.

The tube 20 carries high pressure water and is connected to a pastecartridge receiver 24 secured to the main body portion 10 by a clamp 25.A cartridge containing the prophylaxis material or paste is placedwithin the receiver 24 and locked by a closure member 26 by means of abayonet joint consisting of pairs of oppossite slots 27 and pins 28.Paste is delivered as desired to the interior of the cup 14 by operationof a valve 30 mounted on the handpiece and which is controlled remotelyas by a foot operated pedal. The valve is operated by the admission ofair through the tubing 19 to the valve 30 whereupon the paste isdischarged from the cartridge through a flexible tube 31 passing throughthe valve 30 and connected to a tubing 32 which is preferably rigid andwhich is secured on the body portion 10 and the reduced portion 11 ofthe handpiece. The tubing 32 is detachably connected to a tube 32' onthe tip for delivery of the paste to the head 13 and thence to the cup14. Air and wateer used for drying and flushing purposes are deliveredthrough the tubes 22 and 23, respectively, which are connected to tubes33 and 34, respectively. If desired, both air and water may be suppliedconcurrently through the tubes 22 and 23 to produce a water spray. Thetubes 33 and 34 are secured to the body 10 and detachably engagerespective tube sections 33' and 34' attached to the tip 12 of thehandpiece and terminating in angularly directed tips 35 and 36, as shownin FIGS. 5 and 6, respectively.

From the foregoing, it will be observed that all of the functions of thehandpiece are accomplished by control or supply fluids passing to thehandpiece through the tubes within the tubular casing 16. The casing maybe made highly flexible and may be coiled or otherwise arranged inaccordance with present day dental equipment practice. The manner inwhich the system is controlled will be explained below in connectionwith the description of the fluid and electrical control system. This isa remote control system and all of the functions may be performed by thedentist without changing his hand position on the handpiece and withoutremoving the applicator cup from the working area of the teeth. Theprophylaxis material or paste supplied to the cup is employed in theusual manner and at any time that the dentist wishes to flush theworking area, water is supplied through the discharge tip 36 and thearea can then be dried by supplying air through the tip 35. During theuse of the applicator cup 14 while the cup is rotating it is pressedagainst the surfaces of the teeth and distorted in various directionsdepending upon the requirements of the work. The cup and its mountingare so constructed that although the paste or prophylaxis material ispresent near the bearing surfaces of the head 13, it is prevented fromreaching these surfaces and damaging the bearings.

The details of construction of the head 13 and the mounting for the cup14 are illustrated in FIG. 4 wherein the head 13 is shown asconstituting a short right angled extension of the detachable tip 12.The applicator cup 14 is rotated by operation of a shaft 36 driven bythe motor within the body of the handpiece and which has a beveled gear38 at its end mounted in engagement with a beveled gear 40. The gear 40is journaled on a tube 41 illustrated as formed integrally with thematerial of the head 13 and rotates about this tube as a shaft. The hubassembly of the gear 40 comprises an upper extension 42 and a lowerportion 43 terminating in an attaching member illustrated as a threadedend. The attaching member engages a threaded fitting or adapter 44 shownas a head or bead about which the cup 14 is held. The top end of theextension 42 engages the adjacent top wall of a recess 45 providedwithin the head surrounding the gears 38 and 40. A sleeve or guidebushing 46 is mounted in the top of the recess 45 and acts as an outerbearing or shield for the extension 42. The lower extension 43 isprovided with a slinger ring 47 just above the threaded end which servesto throw outwardly any liquid which reaches it and prevents such liquidfrom flowing onto the bearing surfaces between the extension 43 and abushing 48 in which it is journaled; the bushing is threadedly securedin the head 13.

The prophylaxis material admitted from the tube 32' enters a pasage 50extending across the top of the head 13 and terminating in the tube 41so that the material flows downwardly through the tube 41 and into thecup 14. The cup 14 is made of highly flexible material which is readilydeformed but has sufficient resilience to grip and retain itself on themember 44 during the working operation. The cup comprises an upperportion 51 which is shaped to conform to the adapter member 44 but is ofslightly smaller dimensions so that it is held securely in place when itis stretched over the adapter. The lower portion of the cup is anoutwardly flaring bell 52 formed with internal ribs 53 which facilitatethe cleaning operation. A thick central portion 54 of the cup isprovided with a cylindrical center passage which is preferably of auniform diameter substantially less than the outer diameter of the tube41 so that when the cup is pressed over the bead or threaded on thelower end of the hub assembly the tube 41 extends into the passage for adistance short of the end of the passage. The remaining portion of thepassage wall first bends, at least partially, in face engagement withthe bottom end surface of the tube and then forms in a substantiallyconical or tapering configuration due to the stretching of the cup andthe contraction of the passage toward its bottom end, the opening at thebottom being of the diameter of the unstretched cylindrical passage. Thetermination of the end of the tubing 41 so that it lies within thecylindrical passage in the cup 14 provides a characteristic of themounting whereby the admission of the prophylaxis material to thebearing area of the cup which rotates on the tube 41 is minimized. Thelower end of the cylindrical passage in the cup thus provides arotatable extension of the tube 41. The length of the free passagebeyond the tube 41 may be selected over a wide range; it depends uponthe characteristic of the material of the cup and its configuration. Insome cases the free passage may be very short as compared with that inthe illustrated embodiment. It has been found by repeated tests that aflexible cup as illustrated and with the tube extending only partiallythrough the cylindrical center passage operates to prevent admission ofthe treatment material to the bearing surfaces on the exterior of thetube 41 and that bearing wear due to prophylaxis material is effectivelyeliminated. Leakage or flow of the material around the portion of thecup engaging the bottom end of the tube 41 is prevented, and, regardlessof the pressures and distortions of the cup during operation, thesealing effect is maintained; pressure on the cup as it is presseedagainst the teeth automatically causes a tighter seal between the end ofthe tube and the rotating cup. It has been observed that on directpressure of the cup along the axis of the tube the width of thedischarge opening of the cup at the end of the cylindrical portiondecreases. These characteristics are maintained regardless of thedistortion of the cup, the seal becoming tighter under pressure, eitherdirectly along the axis of rotation or at an angle thereto. Theconstruction of the cup and the arrangement of its mounting on the lowerend of the tube 41 with a portion of the passage in the cup extendingbeyond the tube end provides an efffective rotating seal. For purposesof illustration and in contrast to the operation of the cup of thepresent invention, it has been found that if the end of the tube, suchas the tube 41, extends through the cup into the interior thereof, theoperation and distortion of the cup allows the admission of theprophylaxis material to the bearing surfaces and quickly destroys thesesurfaces including those on the tube 41 and drive gears 38 and 40.

The normal life of the angles or heads of motor driven dental handpieceswhich are used for prophylaxis treatment is short and may, by way ofexample, be of the order of one thousand treatments or about threemonths use. The short life of these heads is due to the presence ofabrasive substance in the prophylaxis treating material or paste whichfinds its way into the bearings. When the handpiece is constructed todeliver the material directly to the treatment area through the flexiblerubber cup the wear of the angle or head bearings becomes severe and anextremely short life makes these handpieces impractical. The presentinvention utilizes compression of the flexible applicator cup to form arotating seal which effectively prevents the abrasive material fromreaching and destroying the bearing surfaces for at least as long a timeas that in which the normal wear of the head renders it unserviceable.Thus the heads of handpieces which embody the delivery of prophylaxispaste to the treatment area through the handpiece are made usable forthe same normal life as the heads of conventional handpieces. The fulladvantage of the feeding of the paste to the treatment zone is thusrealized and the time saving features of direct paste supplying dentalhandpieces are made fully available.

The manner in which the seal is effected is indicated more clearly inFIG. 4a which is an enlarged view of the area of the seal between thesupply tube end and the flexible cup as viewed in FIG. 4. When theflexible cup is pressed over the retaining bead 44 the tube 41 is movedinto the central passage of the cup and expands the wall of the passageuntil the tube is in the position shown, a slightly tapering portion ofthe cup passage extending beyond the end of the tube as shown. Thiscompresses the rubber tightly about the end of the tube and particularlyagainst the annular shoulder or corner edge. The handpiece drive is thenactuated before paste has been applied and the bead 44 is rotated on thetube 41; the cup is rotated about the stationary tube 41 and the rightangle corner of the tube, indicaated at 41a, cuts or wears its way intothe rubber, and, as the rotation continues, forms an effective seal atthe corner which, when the paste is applied, prevents movement of thefluid material around the end of the tube and onto the bearing surface.The seal is formed in two portions: a cylindrical seal 41b about theouter end surface of the tube adjacent the corner and an end face seal41c in a plane normal to the axis of rotation. During application ofpressure and lateral movement of the applicator cup over the treatedsurface there is a tendency for the hub or central portion 54 of the cupto move laterally over the end surface of the tube 41. The motionproduced may, for example, be an eccentric movement of the seal 41c overthe end face of the tube; the seal 41c then maintains face engagementwith the end face over a sufficient area to maintain its seal andprevent the opening of a passage to the outer cylindrical surface of thetube. The distortion of the cup during use thus is prevented fromcausing a separation of the seal which would allow paste to flow ontothe cylindrical bearing surfaces. Thus each cup or applicator forms itsseal when it is positioned on the head and rotated by opeeration of thepower drive. The corner of the tube 41 wears slowly and as it becomesrounded the effectiveness of the seal is gradually lost. It has beenfound, however, that this does not occur before the main bearing of thegear 40 has worn beyond practical usability. By way of example, for somehandpieces an average of one thousand or more applicator cups may beused before the angle or head bearing between the gear 40 and thebushing 48 has worn out so that the head must be discarded. The sealformed by each cup in turn when it is applied to the head as describedabove thus prevents admission of paste to the tube bearing and assuresuseful operatioon of the head or angle for its full normal life.

By employing the highly flexible applicator cup 14 constructed asillustrated and mounted in the manner indicated in FIG. 4, extended useof the cup without bearing wear is made possible and the dentist maywork continuously without difficulty which might otherwise arise wherethe prophylaxis material allowed to reach the bearing surfaces of thehead assembly. The control system of this inventioon has been arrangedto make full use of the advantageous construction of the applicator cupassembly.

As shown in FIGS. 5 and 6, the prophylaxis material passage at the tipof the handpiece may be flushed and cleaned by drawing the tip 12longitudinally away from the reduced position 11 of the handpiece androtating the tip about 180° so that a small diameter connectingextension 56 of the tube 32' may be inserted in and connected to theflushing water supply tube 34. At the same time, the shorter reduceddiameter connecting extension 57 of the tube 34' does not reach or enterthe material supply tube 32 diametrically opposite and remains open.With the tip of the handpice in the position indicated in FIG. 6, theflushing water may be supplied to the tube 34 and run until allprophylaxis material has been cleared out of the tubes 32' and 41.Normally, the flexible cup 14 will be removed before starting theflushing operation.

The cartridge holder or receiver 24 for supplying the prophylaxismaterial under pressure is illustrated in FIG. 8. The cartridge holdercomprises a cylindrical shell 60 having a closed end 61 at the center ofwhich is mounted a sharp pointed piercing tube 62 connected incommunication with the high pressure water supply tube 20 through asealed connection comprising a cap 63 threaded onto an extension 64 ofthe wall 61 and having a sealing gasket 65 for preventing leakage aboutthe tube 20. The other end of the cylinder 60 is open and is providedwith a detachable closure member or block 66 which is held in positionby the bayonet joint previously described. When the cartridge receiver24 is to be loaded with a cartridge, the end piece or block 66 isremoved and the cartridge placed in the chamber. Longitudinal openings67 on either side of the cartridge receiver are provided for access tothe material cartridge. The end block 66 is connected to the flexibletube 31 by a threaded cap 68 and is sealed by gaskeet 70. The member 66has an internal chamber 71 closed by a threaded cylindrical cap 72 andsealed by a gasket 73. The gasket 73 is formed with an integral checkvalve 74 comprising a domeshaped member having a razor slit andextending about the open end of a tube 75 mounted in the cap 72; thetube 75 is a piercing tube for providing communication with the interiorof a material cartridge indicated at 76. The check valve 74 allows theprophylaxis material to flow outwardly into the chamber 71 and thence tothe tube 31 but prevents backflow.

The cartridge 76 comprises a hollow cylinder having flexible rubber-likeplastic ends 77 and 78 which acts as gaskets and are provded withsealing closures or diaphragms near their outer ends which are forsealing their respective central passages indicated at 80 and 81,respectively. Within the space between the ends 77 and 78, there is apiston 82 adjacent the end 77 and a charge of prophylaxis material 83filling the remainder of the cartridge. When the cartridge has beenplaced in the holder 24, the end piece 66 is pressed into position,thereby causing both the piercing tubes 62 and 75 to break the seals intheir respective ends of the cartridge 76 and place the material inposition to be discharged. The discharge of the material from thecartridge is effected by pressure fluid supplied through the tube 20 andwhich moves the piston 82 to the right to force the material 83 outthrough the cartridge and into the tube 31. The tube 20 is a tube ofvery small internal diameter which may be of capillary dimensions andwhich is arranged to receive high pressure water as the driving forcefor the piston 82. After the passages within the cartridge have beenfilled and also the tube 31, the discharge of material from thecartridge is controlled by the valve 30 which, as illustrated in FIG. 9,comprises a spring pressed bail 85 arranged to slide in guides 86between which passes the tube 31. The bail is pressed to the left asshown in FIG. 9 by a helical compression spring 87 which bears against aretainer 88 resting against the guides 86 and a disc 90 which engages apressure diaphragm 91. The spring exerts force sufficient to flatten thetubing so that the passage through the tubing is closed and flow ofprophylaxis material prevented.

When the valve is to be actuated, pressure is admitted through the line19 which is connected to the valve by a nipple 92 and providescommunication with a central passage 93 thereby pressurizing the chamberto the left of the diaphragm and pressing the diaphragm to the right torelease the bail 85. The chamber within the valve housing is maintainedat atmospheric pressure through a vent 94 in the right hand end of thevalve 30. Thus, the diaphragm is free to move the bail when pressure isadmitted to the control chamber on its left.

In order to provide adequate high pressure for discharging theprophylaxis material from a cartridge within the holder 24, a pressureamplifier is provided. This amplifier is illustrated in FIG. 10 andcomprises a cylinder 95 having a left end closure member 96 welded orotherwise suitably bonded to the cylinder 95 and a right end closure orfitting 97 threadedly attached to the cylinder 95 to afford access tothe interior for adjustment or repair. A threaded inlet passage 98 inthe closure 96 communicates with the interior of the cylinder 95 on theleft hand side of a piston 100 which is provided with an O-ring gasketor seal 101 held between a pair of annular rings 102 formed integrallywith the piston 100. A reduced cylindrical section 103 of the piston 100comprises a small diameter high pressure piston operating in a cylinder104 formed within the end fitting 97, which constitutes a cylinderblock, the cylinder 104 being extended by a cylindrical member 105 whichis closed by a fitting 106 terminating in a threaded connection 107. Thepiston 103 is sealed with respect to the walls of the cylinder 104 by anO-ring 109 retained in an annular recess 108 formed in the left hand endof the fitting 97 and closed by a ring 110 welded or otherwise securelyheld thereto. The chamber within the cylinder 95 to the right of thepiston 100 is vented to the atmosphere through an opening indicated at111. High pressure water to be supplied to the capillary tube 20 isadmitted to the cylinder 104 through an inlet passage 112 which entersan annular recess 113 of triangular cross section in the inner walls ofthe cylinder block 97 and confines an O-ring 114 which constitutes acheck valve. In order to actuate the amplifier, air under pressure isadmitted through the connection 98 to the cylinder 95 on the left handside of the piston 100 and moves the piston 103 forward in the cylinder104. As it moves forward, the pressure of the water closes the passageto the inlet 112, the O-ring 114 expanding agaiinst the wall of theannular groove 113 for this purpose; as the piston moves forward itsupplies water under high pressure as required until the piston reachesthe end of its stroke, indicated by dotted lines, or until the charge ofmaterial in the cartridge 76 has been exhausted. Piston 100 may bereturned to its left hand position in any suitable manner and acompression spring 115 may be provided for this purpose. The spring isnot essential as the pressure of the water from the source connected tothe inlet 112 will move the piston to the left when the air pressure isreleased from the left hand end of the piston 100. On the return stroke,water flows from the source through the passage 112, the O-ring 113acting as a check valve and upon full retraction the piston is readyagain for movement to the right and air pressure is admitted to theinlet passage 98 for this purpose. The pressure amplifier provides waterunder high pressure for passage through the capillary tube 20 andpropulsion of the prophylaxis material from the supply cartridge 76. Thetube 20 which carries the high pressure water to the prophylaxismaterial propelling device may be a tube of any suitable material ofsufficient strength to carry the required high pressure.

The controller and regulating system for the supply of fluids to thehandpiece is shown in FIG. 11. The system is prepared for operation byinserting an electrical plug 116 in a suitable three-terminal socket toconnect the system to the power main and to ground. The control systemincludes a water inleet 117 to provide a supply of water for a heater118 and thence to supply the water utilizing circuits through a conduit120. The water heater is heated electrically, current being suppliedthrough lines 121 and 122 upon closing of a switch 123 in the line 122.A suitable thermostatic control 119 is provided to maintain the desiredwater temperature. Closing of the switch 124 connects solenoids 125 and126 to be energized thereby moving two position valves 127 and 128 fromtheir lower or U-turn positions to their upper or straight throughpositions. These are three-way valves and control the supply of air tothe water pressure amplifier 95 and the supply of water from theamplifier to the high pressure line 20. Water is supplied from the line120 to the inlet 112 to the cylinder 105 to the water amplifier througha line 130.

When the pressure amplifier applies high pressure water through the tube20 to the piston 82 of the cartridge 76 prophylaxis material 83 isexpelled from cartridge 76 through line 31. The displaced prophylaxismaterial 83 on the right side of the piston 82 is replaced by the watersupplied by the tube 20 on the left side of piston 82. The pressures inline 20 and line 31 and their respective central passages 80 and 81 areequal. Whenever the expulsion of prophylaxis material 83 is stopped, thecheck valve 74 prevents back flow of prophylaxis material from tube 31to the cartridge 76 through the passage 81. When solenoid valve 128 ismoved to its release or U-turn position, water under high pressure inthe cartridge 76 to the left of the piston 82 is released through line20 to the U-turn passage of solenoid valve 128 in a manner describedbelow. This reduction in water pressure to atmospheric pressure to theleft of the piston 82 allows the prophylaxis material 83 under highpressure to force the piston 82 to the left only slightly resulting inatmospheric pressure on prophylaxis material in the cartridge 76. Thuswhen the water to the left of the piston 83 and the prophylaxis materialto the right of the piston 83 are at atmospheric pressure, the cartridge76 can be removed without expelling any remaining prophylaxis materialfrom cartridge 76 through the connecting passage 81 or expelling waterthrough the connecting passage 80. The seals 77 and 78 close on removalof the cartridge 76 and prevent any gravity release of water andprophylaxis material through the passages 80 and 81 respectively. Thusthe cartridge 76 can be placed in the cartridge holdeer 24 and theprophylaxis material 83 in the cartridge 76 can be used in whole or inpart and the cartridge 76 removed and discarded in a clean and efficientmanner.

Water for supply to the line 23 flows from line 120 through a filter131, a pressure regulator 132, and a normally closed two position on-offvalve 133. The valve 133 is actuated by a dolenoid 134 which isenergized on closing of a switch 135 in a foot control switch assembly136, upon opening of the valve water flows through the line 23 forflushing and irrigating the mouth.

The foot control 136 indicated diagrammatically in FIG. 11 is of a typegenerally employed with dental equipment and may be of any suitableconstruction; the control is arranged so that the operator may actuateany one or more of switches 135, 137, 138 and 139, depending upon theoperation or operations which he is performing. Closing the switch 137energizes a solenoid 141 to open a normally closed two way on-off valve142 and supply air to the line 22 at a pressure determined by thesetting of a regulator 143. The closing of the switch 138 energizes asolenoid 144 to open a valve 145 and supply air under pressure to theline 19 which actuates the prophylaxis paste release valve 30. Thepressure in line 19 is controlled by a regulator 146 and is indicated bya gauge 147. When the solenoid 144 is released the valve 145 is in itslower position and connects the line 19 through the U-passage in thevalve to the atmosphere for release of pressure. Closing of the switch139 energizes the air turbine control which in accordance with thepresent practice is usually located adjacent to the dental chair; thecontrol includes an arrangement for adjustment of the speed of themotor. The air for the turbine is supplied to the handpiece control boxor panel through a line 15', and the turbine control on the consoleprovides for selection of the turbine speed. The details of the turbinespeed control are not illustrated as they are not essential to anunderstanding of the present invention. The turbine control on theconsole supplies air directly to the line 15 at the required pressurefor the selected condition of operation. All air supplied to the controlsystem is cleaned by a filter 148. The air supplied to the waterpressure amplifier through the valve 127 is at a pressure controlled bya regulator 150 and indicated by a pressure gauge 151. When the valve127 is in its lower position, as illustrated in the drawing, the airpressure in the water pressure amplifier 95 is atmospheric, it beingreleased through the U-passage in the valve. In a similar manner, thevalve 128 in its lower position, as shown in the drawing, connects thewater pressure line 20 to a conduit 152 to deliver the excess water to areservoir 153, a check valve 154 being provided in the line 152. Thepressure in line 20 is thus released whenever the solenoid 126 of thevalve 128 is de-energized.

The volume of the water delivered through the tube 20 may be controlledby operation of a valve 156 connected between the water pressure chamber105 and the three-way valve 128. The valve 156 is an adjustable valveand, for example, may be a needle valve; for convenience in selectingthe pressure at the valve outlet, the valve is provided with anindicating dial shown in FIG. 12. On this dial there are indicated fivepressure positions, a LOAD position and a FLUSH position, the extremeposition on turning the valve clockwise being the OFF position. As thevalve is turned, it moves from the OFF position through the first fivepositions and then to the LOAD and FLUSH positions in turn. The LOADposition allows a greater flow than any of the five positions and theFLUSH position provides a greater flow than that of the LOAD position.When a cartridge 76 is to be loaded into the holder 24, the switch 124is opened and the solenoids 125 and 126 are de-energized; the waterpressure is thereby released and the line 20 opened to the conduit 152.The cartridge is then placed in the holder 24 and the dial of FIG. 12set at its LOAD position, whereupon the solenoids 125 and 126 areenergized and water is again supplied through the tube 20. In the LOADposition, the water flows at an optimum rate to allow prophylaxismaterial to flow through the tube 31 to the valve 30 when the valve 30is open, whereupon the material passes through the tubes 32 and 32', andthence through the passage 50 to the applicator cup 14. The valve 156 isthen set at one of the five operating positions indicated on the dialand the prophylaxis treatment is given the patient. Upon completion ofthe treatment, the head of the handpiece may be flushed as describedheretofore. Thereafter loading requires only the filling of the passagesin tubes 32' and 41 to ready the handpiece for further use.

When it is desired to flush the entire handpiece system, the piston 82in a cartridge 76 is removed from the cartridge, and the cartridge isreturned to the handpiece. The dial of the valve 156 is then turned tothe FLUSH or high volume water position, the valve 30 and the solenoidvalve 128 are opened, and water then flows continuously from the conduit130 through the inlet passage 112 to the valve 156 and the entireprophylaxis material handling conduits of the system are thereby flushedwith water for as long a period as desired.

The action of the system to release prophylaxis material by operation ofthe valve 30 is such that by tapping the foot switch 138 a very smallsupply or short of the prophylaxis material may be admitted to theapplicator cup 14, the action being such that the bail 85 in the valve30 may be released for a brief moment. When the bail is returned to itsspring biased position the resulting squeeziing or flattenting of thetube 31 aids the final extrusion of paste on each operation. The amountof paste supplied to the cup 14 may thus be varied from a very smallamount to an excess of that required to fill the cup or a continuousflow if desired. The entire control of the supply of the paste iseffected by the remote control at the foot switch. By actuation ofselected functions of the foot control uniit, the dentist may continuehis work without interruption and may clean and polish the teeth, flushthem with water, and dry them for inspection as he desires. The turbineor motor is, of course, operated at the desired speed selected at theconsole and in the usual manner and is energized by remote control. Thecontrol system is highly effective and precise in operation and savessubstantial time in the use of the prophylaxis equipment. Furthermore,the design of the mounting arrangement for the flexible applicator cupis such that wear of the instrument becomes negligible and interruptionof work for replacement of the tip and head of the handpiece isminimized.

We claim:
 1. In a dental prophylaxis apparatus of the type having ahandpiece including means for supporting a rotatable flexible applicatorcup and means for supplying fluid treatment material to the interior ofthe applicator cup a control system comprising:drive means for rotatingsaid cup; means connectable to a water supply for receiving water andfor amplifying the pressure thereof and having an outlet for thedischarge of high pressure water; a compressible chamber reservoir forholding a supply of treatment material therein; a fluid line forconducting treatment material from said reservoir to the interior of theapplicator cup; a normally closed valve mounted on said handpiece andconnected in said fluid line; means connected to the outlet of saidamplifying means for utilizing high pressure water for compressing saidchamber and forcing treatment maaterial into said line; and footcontrolled quick acting means for selectively opening and closing saidvalve for intermittent short periods to charge the applicator cup withselected amounts of fluid treatment material whereby the operator'shands are completely free to manipulate the handpiece withoutinterruption and the applicator need not be removed from the patient'smouth.
 2. A dental prophylaxis apparatus as set forth in claim 1 whereinsaid normally closed valve comprises a length of flexible tubingconnected in said fluid line as a portion thereof and biasing means fornormally pinching said tubing closed.
 3. A dental prophylaxis apparatusof the type having a handpiece including means for supporting arotatable flexible applicator cup and means for supplying fluidtreatment material to the interior of the applicator cup a controlsystem comprising:drive means for rotating said cup; means connectableto a water supply for receiving water and for amplifying the pressurethereof and having an outlet for the discharge of high pressure water; acompressible chamber reservoir for holding a supply of treatmentmaterial therein; a fluid line for conducting treatment material fromsaid reservoir to the interior of the applicator cup; a normally closedvalve in said fluid line; means connected to the outlet of saidamplifying means for utilizing high pressure water for compressing saidchamber and forcing treatment material into said line; manuallycontrolled quick acting means for selectively opening and closing saidvalve for intermittent short periods to charge the applicator cup withselected amounts of fluid treatment material; said normally closed valvecomprising a length of flexible tubing connected in said fluid line as aportion thereof and biasing means for normally pinching said tubingclosed; and said biasing means comprising a compression spring, a rigidstop member, and a bail extending across the side of said flexibletubing opposite said stop, said spring being mounted to press said bailagainst said tubing to collapse and close said tubing against said stopby the force of said spring, said bail on collapsing said tubingpinching said tubing and effecting a displacement of a small amount oftreatment material.
 4. A dental prophylaxis apparatus as set forth inclaim 3 including fluid pressure means for releasing said bail from saidtubing, and a remote actuating means for controlling the flow of fluidto said pressure means.
 5. A dental prophylaxis apparatus as set forthin claim 1 including conduit means mounted on said handpiece andterminating in discharge tips directed toward the zone of said cup, andremote control means for supplying water to one of said conduits and airto the other of said conduits whereby the treatment may be effected bythe use of said rotatable cup and treatment material and the area oftreatment thereafter washed by application of flushing water and driedby air without requiring removal of the head of the handpiece from thepatient's mouth.
 6. A dental prophylaxis apparatus as set forth in claim5 wherein said handpiece comprises a removable end portion comprisingsaid means for supporting said flexible applicator cup and wherein saidconduits are drawn apart and separated on longitudinal movement of saidportion away from said handpiece and said fluid line is similarlydetachable and removable, the fluid line on said end portion having aportion of reduced diameter for engagement with the portion thereof onthe handpiece and said water conduit having a similar but longer portionof reduced section whereby said end portion of the handpiece may berotated after release from the main portion of the handpiece and saidlonger reduced portion inserted in said water supply conduit fordirecting water through said treatment material supply for flushing thefluid supply line on said detachable tip portion.
 7. A dentalprophylaxis apparatus as set forth in claim 5 including a single footoperated control unit including said quick acting means for selectivelyactuating and controlling said water supply means and said air supplyingmeans and said means for selectively opening and closing said valve. 8.A dental prophylaxis apparatus as set forth in claim 1 wherein saidcompressible chamber reservoir comprises a removable cartridge having apiston therein and a charge of treatment material, and means forconnecting the discharge end of said cartridge to said fluid line andthe opposite end of said piston to said pressure amplifying means.
 9. Adental prophylaxis apparatus as set forth in claim 1 wherein the meansfor rotating the flexible applicator comprises a motor mounted withinsaid handpiece, and a remote foot controlled means for selectiivelyactuating said motor and said water supply means and said quick actingmeans for opening and closing said valve.
 10. A dental prophylaxisapparatus of the type having a handpiece including means for supportinga rotatable flexible applicator cup and means for supplying fluidtreatment material to the interior of the applicator cup a controlsystem comprising:drive means for rotating said cup; means connectableto a water supply for receiving water and for amplifying the pressurethereof and having an outlet for the discharge of high pressure water; acompressible chamber reservoir for holding a supply of treatmentmaterial therein; a fluid line for conducting treatment material fromsaid reservoir to the interior of the applicator cup; a normally closedvalve in said fluid line; means connected to the outlet of saidamplifying means for utilizing high pressure water for compressing saidchamber and forcing treatment material into said line; manuallycontrolled quick acting means for selectively opening and closing saidvalve for intermittent short periods to charge the applicator cup withselected amounts of fluid treatment material; said pressure amplifyingmeans comprising a cylinder having a reciprocable piston therein, aconcentric cylinder of reduced diameter extending from said firstcylinder and a second piston secured to and extending from said firstpiston and reciprocable in said second cylinder, said second cylinderhaving an inlet in the side wall thereof and a water outlet in the endwall thereof, said side wall having an annular recess communicating withsaid inlet, an O-ring gasket in said recess, said gasket acting as acheck valve for closing said inlet on the pressure stroke of saidpiston, and means for admitting fluid under pressure to said firstcylinder for forcing said first piston towards said second cylinderwhereby water is forced out under pressure through the outlet of saidsecond cylinder.
 11. A handpiece for dental prophylaxis apparatusincluding a hollow stationary shaft, an applicator cup support rotatablymounted on said shaft, means for rotating said support about said shaft,said support having a cup attaching means near its outer end and saidshaft extending beyond said attaching means, a conical outwardly flaringflexible prophylaxis cup having a base provided with a recess forreceiving said attaching means and a cylindrical center passage forreceiving the end of said hollow shaft and for conducting fluid fromsaid shaft, said center passage extending beyond the end of said shaftand having a smaller diameter than the external diameter of said shaftwhereby the wall of said passage tends to close about and beyond the endof said shaft, said cup being rotatable about the end of the shaft andsealing the bearing surface of said support against the admission oftreatment material thereto, the contraction of said central passagebeyond said shaft upon distortion of said cup during use maintaining thesealing engagement of said cup and said shaft.
 12. A handpiece head fordental prophylaxis apparatus as set forth in claim 11 including aslinger ring mounted on said support and spaced axially from said cupattaching means on the side thereof remote from said cup.
 13. In adental prophylaxis apparatus of the type having a handpiece includingmeans for supporting a rotatable flexible applicator cup and means forsupplying fluid treatment material to the interior of the applicatorcup, a control system comprising:drive means for rotating said cup;means connectable to a water supply for receiving water from the supplyand having an outlet for the discharge of high pressure water; adiscardable cartridge of cylindrical configuration having a pistontherein adjacent one end and being filled with treatment materialbetween said piston and the other end thereof; a fluid line forconducting treatment material to the interior of the applicator cup;means for receiving said cartridge and for connecting the interior ofsaid cartridge with said water pressure outlet at said one end and tosaid fluid line at said other end; means utilizing said high pressurewater for forcing material for intermittent short periods from saidcartridge to charge the applicator cup with fluid treatment material;and a single foot operated control unit for selectively actuating andcontrolling said drivve means and said means for utilizing said highpressure water to charge said applicator cup.
 14. A dental prophylaxisapparatus as set forth in claim 13 including pressure amplifying meansfor amplifying the pressure of water from said water receiving means,said outlet communicating with and supplying water from said pressureamplifying means.
 15. A dental prophylaxis apparatus of the type havinga handpiece including means for supporting a rotatable flexibleapplicator cup and means for supplying fluid treatment material to theinterior of the applicator cup, a control system comprising:drive meansfor rotating said cup; means connectable to a water supply for receivingwater from the supply and having an outlet for the discharge of highpressure water; a removable cartridge for holding a supply of treatmentmaterial therein; a fluid line for conducting treatment material fromsaid cartridge to the interior of the applicator cup; means including apiston connected to said outlet for the discharge of high pressure waterfor compressing said cartridge and forcing treatment material into saidline; means for applying said high pressure water to said piston forintermittent short periods to charge the applicator cup with fluidtreatment material; a single foot operated control unit for selectivelyactuating and controlling said means for applying said high pressurewater to said cartridge and said drive means; said apparatus includingpressure amplifying means for amplifying the pressure of water from saidwaater receiving means, said outlet passing from said pressureamplifying means; and said pressure amplifying means comprising acylinder having a reciprocable piston therein, a concentric cylinder ofreduced diameter extending from said first cylinder and a second pistonsecured to and extending from said first piston and reciprocable in saidsecond cylinder, said second cylinder having an inlet in the side wallthereof and a water outlet in the end wall thereof, said side wallhaving an annular recess communicating with said inlet, an O-ring gasketin said recess, said gasket acting as a check valve for closing saidinlet on the pressure stroke of said piston, and means for admittingfluid undeer pressure to said first cylinder for forcing said firstpiston towards said second cylinder whereby water is forced out underpressure through the outlet of said second cylinder.
 16. In aprophylaxis treatment dental handpiece of the type including a stationaycylindrical tube for delivering a supply of fluid treating material tothe interior of a flexible applicator cup rotatable with respect to thetube, the improvement which comprises an applicator fittiing mounted forrotation on said tube, the outer wall of said tube constituting abearing surface, a flexible applicator cup constructed to be mounted onsaid fitting, and means for utilizing a portion of the flexibleapplicator cup mounted on said fitting for providing a rotating sealbetween the end of said tube and said applicator cup and for preventingradially outward movement of fluid between said applicator cup and saidtube toward the bearing surface on the outer wall of said tube.
 17. In aprophylaxis treatment dental handpiece of the types including astationary cylindrical tube for delivering a supply of fluid treatingmaterial to the interior of a flexible applicator cup rotatable withrespect to the tube, means including a cup driving fitting rotatableabout said tube for rotating said cup and for retaining the applicatorcup about the end of said tube, said tube extending beyond said fitting,and means for providing between said tube and said applicator both acylindrical seal about the outside of said tube and a radial seal on theend face thereof whereby fluid is prevented from moving outwardly overthe end of said tube and into thee cylindrical seal.
 18. The inventionof claim 16 wherein said tube is formed with a relatively sharp angledshoulder around its outer circumference and said applicator cup isconstructed with an axial bore having a diameter less than the outerdiameter of said tube and longer than the extension of said tube beyondsaid fitting whereby said applicator cup when mounted on said fitting iscompressed about the end of said tube.
 19. The invention of claim 18wherein the end face of said tube is flat and lies in a plane normal tothe axis of the tube, said shoulder being of right angled configuration,and wherein said rotating seal is formed by face engagement of aradially extending flat portion of the wall of said bore with said endface of said tube.
 20. In a prophylaxis treatment dental handpiece ofthe type including a stationary cylindrical tube for delivering a supplyof fluid treating material to the interior of a flexible applicator cupand a driving member rotatable about said tube and having a cupattaching element thereon and said tube extending beyong said drivingmember, the method of forming an effective rotating seal between thetube and the cup which comprises:providing the cup with a central axialbore longer than the portion of said tube extending beyond said memberand having a diameter less than the outside diameter of said tube;mounting the cup on the fitting with the wall of the bore compressedabout the end of the tube; and while keeping the wall of the bore dry,rotating the cup about the tube to wear an annular sealing surface inthe wall of the bore adjacent the end of said tube.
 21. The invention ofclaim 16 including means effective upon the application of axialpressure on said cup in a direction toward said fitting for increasingthe tightness of the seal between the end of said tube and saidapplicator cup.
 22. The invention of claim 21 wherein said applicatorcup comprises a thick base portion for mounting on said fitting and acupped portion extending axially therefrom, and wherein said lastmentioned means utilizes the transmission of forces through said cuppedportion during use of said applicator and for effecting said increasingof the tightness of said seal.
 23. As an article of manufacture, adental prophylaxis material applicator for use on dental handpieceshaving means for delivering prophylaxis material through the handpiece,said applicator comprising a body of resilient highly flexible materialhaving an end portion constructed for attaching the applicator to arotary drive member and an adjacent thick central hub portion and athick walled cup shaped portion concentric with said hub and extendingaxially therefrom, said hub portion having a central cylindrical passageextending therethrough and opening into said cup portion, said cupshaped portion being constructed to transmit to said hub portionpressure exerted axially against said applicator from the open end ofthe cup toward said hub portion, said hub portion being constructed tobe rotated about a fixed shaft pressed into said passage, whereby when ashaft extends only partway through said passage, a seal is provided atthe shaft end and pressure exerted axially on the cup will tend to closethe passage adjacent the end of the shaft and increase the sealingeffect.
 24. The invention as set forth in claim 23 wherein said cup isof conical configuration and has its walls tapering from said hub towardthe outer edge of the cup.
 25. A dental prophylaxis apparatus as setforth in claim 8 wherein said connecting means includes a recievermounted on said handpiece and comprising a shell closed at one end forreceiving said cartridge and a detachable closure member at its otherend, piercing tubes mounted in said closed end and in said closuremember, said cartridge having piercible ends, and said piercing tubesbeing positioned for engagement with respective ends of said cartridgeand upon pressing said detachable member into position to close saidshell said piercing tubes both being forced through said cartridge endsto connect the discharge end of said cartridge to said fluid line andthe piston end to said pressure amplifying means.
 26. A dentalprophylaxis apparatus as set forth in claim 13 wherein said connectingmeans includes a receiver mounted on said handpiece and comprising ashell closed at one end for receiving said cartridge and a detachableclosure member at its other end, piercing tubes mounted in said closedend and in said closure member, said cartridge having piercible ends,and said piercing tubes being positioned for engagement with respectiveends of said cartridge and upon pressing said detachable member intoposition to close said shell said piercing tubes both being forcedthrough said cartridge ends to connect the discharge end of saidcartridge to said fluid line and the piston end to said pressureamplifying means.
 27. In a dental prophylaxis apparatus of the typehaving a handpiece including means for supporting a rotatable flexibleapplicator cup and means for supplying prophylaxis treatment material tothe interior of the applicator cup, a control system for facilitatinguninterrupted prophylaxis treatment which comprises:drive means forrotating the applicator cup; reservoir means for holding a quantity oftreatment material; a fluid line for conducting treatment material fromsaid reservoir means to the interior of the applicator cup; meansutilizing fluid pressure for forcing treatment material from saidreservoir means through said fluid line to the interior of theapplicator cup; means connectable to a fluid pressure supply foradmitting fluid under pressure to said fluid pressure utilizing means;and foot controlled means for selectively actuating said drive means torotate the cup and for effecting operation of said fluid pressureutilizing means to deliver desired quantities of treatment material tothe cup, whereby the opeerator's hands are completely free to manipulatethe handpiece without interruption and the applicator cup need not beremoved from the patient's mouth for material supply purposes.